Meme Collision Produces 2D Code Stencils

Matt Jones's invention of warchalking back in 2002 was a lark. It combined the culturally laden notion of chalk signs made by hoboes with the modern nomadic lifestyle of the digerati. As packs of laptop wielders roamed from place to place, a warchalk indicating an open Wi-Fi network would allow those network grazers to stop a moment, and fill up on protein-rich memes.

It was a good project, something that dwelt in the space between meme, prank, and urban near-myth. (I believe BoingBoing has a set of gleaming towers reaching to the sky in that space.) But it didn't become self perpetuating. You can see its remnants in the iconography Jones and others developed for open and closed Wi-Fi networks, which were adopted and used in signage and company logos. The reversed parentheses )( for an open network were particularly brilliant, as it requires no graphics program nor keen hand to type or draw.
I propose that QR_STENCILER and QR_HOBO_CODES are warchalking's direct descendants. I've had a multi-year obsession with QR Codes, one form of two-dimensional tags that can encode information densely in a rectangle for recovery through image capture on a mobile or other device. Snap a picture of a 2D tag with the right software--available for free or fee on nearly all smartphones and many feature phones--and the dots and shapes are translated into text, a URL, or other matter. (See this BoingBoing piece from November 2010, for instance, which explains how to generate QR Codes from a bookmarklet, among other information.)
The QR Code project from Free Art & Technology (F.A.T.) is quite charming in its combination of trends, technology, and cultural markers. Like warchalking, the project takes off from hobo signs, which date back over a century--read this lovely account from a 1904 New York Times story. Hoboes would chalk a code to indicate whether one could get a handout, whether there were dogs, and other knowledge to pass along to the next traveler.
F.A.T. created a set of a 100 signs encoded as text in QR Code format (QR_HOBO_CODES), donated to the public domain, and ready for use in its QR_STENCILER software. The software for Mac OS X creates a laser cutter ready file, including coping with the difficulty of making a stencil of symbols that can have floating squares in empty fields. Tricky stuff, and their images make it look like they've figured out the right approach, although parts of these stencils will certainly be fragile. (The software is licensed under Creative Commons for non-commercial use with attribution on share-alike basis.)
QR Codes and other 2D tags are resilient to fairly major distortion. It looks from the code previews that F.A.T. chose a small size over adding more error correction, which increases the number of symbols necessary. That should be fine in practice, as a lack of distortion, clear edges, and contrast are the most important elements for tag interpretation.
The likelihood is that QR_HOBO_CODES will be just as long lasting as warchalking signs, in that they may affect the culture, but not be used much in practice. I pray to his noodle-y majesty that I am wrong about that, but I've seen the memes come and go.
QR_STENCILER could pack more impact, both in making it easy to create and use such 2D tag stencils--the makers suggest a chalk spray, by the way--and encouraging those frustrated with its inevitable limits to create their own software. In fact, I wouldn't be surprised to shortly see templates for using 3D printers to make stencils that produce 2D tags.
(Thanks to Ren Caldwell!)

About the Author

Glenn is a veteran technology journalist based in Seattle who regularly contributes to the Economist, Macworld, Boing Boing, Six Colors, TidBITS, and other publications. He's been blogging since 2001 at his Glog. In October 2012, Glenn won Jeopardy! twice. He tweets @glennf.

Wow, I was actually just considering a very similar QR-code stencil idea for a youth class I taught on graphic arts but I couldn’t find a cost-effective way to make the laser cut stencils. Anyone know a cheap laser-cutting service in the San Francisco Bay area, or a place that might offer free or discounted rates for an educational non-profit organization?

Hi,
This laser-cutting method is really amazing, because it allows you to make many stencils quickly, and accurately. But laser cutters can be hard to find. You might be interested in the method that I created to do the same thing using just chicken wire and caulk to make the stencils: http://www.fredtrotter.com/2011/06/11/making-qr-code-stencils/

â€œThis is one of the few instances where a QR code is actually useful. Instead of their usual environment – slapped on ads and flyers when it would be simpler just to write out the URL or textâ€
Simpler perhaps if you’re prepared to fish around for a pen and a bit of paper, or scribble said URL on your hand, hoping it won’t smudge or get washed off before you can get to a computer, or stand in a shop with a magazine or product in one hand and smartphone in the other, trying to tap the URL into an open web browser.
On the other hand you can have a particular app like Redlaser, Optiscan, or Quickmark open, quickly scan the code and walk away, with the information available for perusal later. Having done the first thing numerous times I know which version I prefer. I use Redlaser a lot for keeping a record of books or CD’s I see that I might want to buy later on; I used it six times in one store yesterday to keep a record of books I’d not seen before that look interesting. The same is true of QR codes; I have that information available for later, and I don’t worry about losing a bit of paper or washing the info away.

I have been thinking about something like this to make urban environments more interactive. Ever wander around a foreign city and see a cool building and wonder what the story behind it is? How cool would it be to walk up to it and discover a QR tile that links to its history in several different languages? Or how about a tour of a city where you are told only where the start is and then you have a tour / scavenger hunt for the places and QR codes that will lead you to the next place. There are so many possibilites for this kind of tech beyond just “hey somebody has an unlocked WiFi network over here!”

On a practical note, yes stickers make sense. I have also been thinking of printing them out to fit on a 4×4 tile and then polyeurethaning them onto the surface and then epoxying that to whatever. Durable, easy to apply, hard to remove. Great for places where there is street art. Have a place specific flickr pool for a grafitti wall so that you can see the art as it changes and evolves over time.

Yeah physical QR codes are often problematic – I’ve encountered several that couldn’t be decoded, even by taking a high resolution DSLR photo and trying to decode it later on a computer (after my smartphone couldn’t do it on the fly).

There were some spraypaint stenciled QR codes on the ground at MakerFaire SF a couple months ago – I came across one about halfway through the first day and it was already unreadable (if it ever worked in the first place). I walked by a while later and there was another guy also obviously having trouble decoding it so it wasn’t just me :)

And I’ve also come across quite a few that were printed on advertisements or on product boxes that couldn’t be read – sometimes they’re too small, and sometimes they just inexplicably don’t work.

Also, I tried to decode this sample stencil in four different Android programs and none of them could do it.

Where are you going to find a laser cutter? At Techshop, of course :-)

The question I’d have about QR code stencils is whether QR codes are designed in a way that you can depend on them being one piece that stays together, as opposed to having disconnected islands that you can’t use in a stencil. I suppose you could get fancy and have thin strips anchoring the islands in place and hope spray paint fills in around them?

I believe the hobo-QR code for a free laser cutting service is something like a big square with some smaller squares in it. Should be fairly easy to recognise. ;-)

Seriously, I kind of like this idea, as a geek, I don’t feel like putting up a sign outside my house saying “3d printer here” and getting brainless trolls asking me to do hours of 3D CAD for free and then print off whatever inane shite they think is funny/necessary .
But another geek who has done his CAD and just needs someone to realise a spare part for his currently broken printer or other fun project, I would be happy to meet.
Having a QR code outside my house would probably only be understood by the geeky types and not the general braindead passerby.
And I can probably print a QR code out of smaller panels…

This is one of the few instances where a QR code is actually useful. Instead of their usual environment – slapped on ads and flyers when it would be simpler just to write out the URL or text – in this case it’s actually valuable that the QR codes are creating a barrier for entry: disguising the intent from most passersby, but still available to anyone who takes the time to engage.

The project is definitely clever, but the main roadblock for widespread adoption is simply that SSIDs come and go (and change) faster than a team of stencilers could proliferate the QR codes.

I think too that the laser cutter is nice but overkill. As our space program wraps up its last mission I would like to point out that NASA spents tens of thousands of dollars creating a pressurized pen cartridge to write with in space. The Russian space program used a pencil. Think of Occam’s Razor here, the less moving parts and expense the better. AMIRITE?

…not to mention that the wood in pencils is flammable in a pressurized pure-oxygen atmosphere.

The real story turns the “stupid NASA” meme on its head – private industry invests the capital to create a useful pen for NASA without any government funding, sells ‘em to NASA for three bucks apiece, and makes a fortune selling them to the space-struck public.

You can still buy them today, and they’re quite handy for times when you need to write upside-down, or on slick or glossy surfaces.

I like the idea of tagging with QRCodes, but think that one-off stencils are not the best way to do it, as they are subject to saturation, falling apart, etc. They are also limited to a single datagram and require specialized cutting equipment or a lot of patience with an Xacto.

A better way would involve a personal projector and a pair of purpose specific spray cans:

â€¢ Decide on your datagram to be encoded and prepare
format it into a QRCode image (many sites will do
this for free).
â€¢ Set up your pocket projector someplace steady (tripod?)
to project your QRCode onto the targeted surface,
projecting in dim red light.
â€¢ Spray can ONE is a red-light-insensitive photographic
emulsion.
â€¢ Coat the targeted surface with the emulsion
(from spray can ONE).
â€¢ Without moving the projector, change to projecting
white light for a limited period of time (a couple
seconds), then return to projecting dim red light
â€¢ Apply Spray can TWO (The Fixer).

I like the system for automatically creating bridges to the islands in the stencil, but it could be better. The islands in the stencil above are only coming down from the top. This will work OK for a stencil cut our of hardboard, but it would be much better to have bridges on the bottom as well for a much sturdier piece.